TryParse & out in C#

Parsing that reports failure instead of throwing.

// TryParse reports success and hands the value out through a parameter
if (int.TryParse("128", out var value))
{
    Console.WriteLine($"parsed {value}");
}

var inputs = new[] { "3", "x", "77" };
var sum = 0;
foreach (var text in inputs)
{
    if (int.TryParse(text, out var n)) sum += n;
    else Console.WriteLine($"skipping '{text}'");
}
Console.WriteLine($"sum {sum}");

How it works

1. int.TryParse returns a bool and fills an out variable.
2. out var n declares the target right at the call site.
3. The loop keeps the good values and names the bad input.

Keywords and builtins used here

• else
• foreach
• if
• in
• int
• new
• out
• value
• var

The run, in numbers

Lines

14

Characters to type

363

Tokens

83

Three-star pace

90 tpm

At the three-star pace of 90 tokens a minute, this run takes about 55 seconds.

Type this snippet

Step 3 of 3 in Methods, step 17 of 29 in Language basics.

← Previous Next →